William Harris, M.D. -- The Scientific Basis of Vegetarianism
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Too much tofu induces ‘brain aging,' study shows
By Helen Altonn
Honolulu Star-Bulletin

Tofu is touted for its health benefits, but also may pose health risks, says a Hawaii scientist.

In comparing the dietary habits and health of the Japanese-American men in the study group between 1965 and 1993, Dr. Lon White said the scientists found "a significant link between tofu consumption during midlife and loss of mental ability and even loss of brain weight."

William Harris, M.D. writes: On 11/30/99 I took 16 samples of soy products for an aluminum assay to University of Hawaii at Manoa College of Tropical Agriculture and Human Resources. Agricultural Diagnostic Service Center 1910 East-West Road Sherman 134, Honolulu, Hawall, 96822.

The results reported on 12/9/99:

The results of this preliminary investigation suggest that the aluminum concentration in soy products is increased slightly by cooking, particularly in an aluminum pot, and strongly (as much as 15-fold) by some methods of tofu production.

Samples 7, 11,13,14, 15, and 16 are produced in Hawaii. I will not release the manufacturer's names unless requested to do so by the companies en mass and for the purpose of reviewing their production methods.

The United States Environmental Protection Agency (EPA), while apparently having no primary toxicity range for aluminum in food suggests 0.05 to 0.2 mg/L (.05 to 0.2 ppm) for water in its National Secondary Drinking Water Regulations:

http://www.epa.gov/OGWDW/wot/appa.html#Inorganic Table 1

At: http://www.fedreg.com/federalregister/data/12dec/12_10_165.html

There is a listing for Aluminum in water at a pH 6.5-9.0 of 750 mcg/L (.75 mg/L or .75ppm)

The lead author in the as yet unpublished recent study implicating tofu as a risk factor for Alzheimer's disease in male Japanese living in Hawaii does not endorse the aluminum-Alzheimer's hypothesis and suggests that isoflavones in tofu are the etiologic factors.

The published articles

White, L., Petrovitch, H., Ross, G.W., & Masaki K.H. (1996) Association of mid-life consumption of tofu with late life cognitive impairment and dementia: The Honolulu-Asia Aging Study. The Neurobiology of Aging, 17 (suppl 4), S121.

White, L., Petrovich, H., Ross, G. W., Masaki, K. H., Abbot RD, et al. (1996) Prevalence of dementia in older Japanese-American men in Hawaii. JAMA, 276, 955-960.

The majority of the Alzheimer's research community also rejects the aluminum hypothesis, so Dr. White is on fairly solid ground here. A nice collection of references supporting the tofu-genistein-isoflavone/Alzheimer hypothesis can be found at:


This site also has the Honolulu Star Bulletin report of Dr. White's Tofu/Alzheimer's study that has not yet been published.

However there are still some lively academic voices suspecting a role for aluminum in Alzheimer's and other neurodegenerative disease. A few can be found referenced at:

http://www.bio.unipd.it/~zatta/alumin.htm http://www.tv.cbc.ca/healthshow/pastitem/adandal.html http://student.biology.arizona.edu/ad/reference.html http://student.biology.arizona.edu/ad/allevels.html

The following references can be researched at:


Clauberg M., and Joshi, J.G. "Regulation of serine protease activity by aluminum: Implications for Alzheimer disease." Proceedings of the National Academy of Sciences of the United States of America. 90 (1993) 1009-12.

Fasman, G D., and Moore, C.D. "The solubilization of model Alzheimer tangles: Reversing the b-sheet conformation induced by aluminum with silicates." Proceedings of the National Academy of Sciences of the United States of America. 91 (1994): 11232- 11235.

Ghany, M.A. et al. "Aluminum-induced Nonenzymatic Phospho-incorporation into Human Tau and Other Proteins." The Journal of Biological Chemistry. 268 (1993): 11976- 11981.

Hollosi, Miklos et al. "Stable Intrachain and Intrachain complexes of neurofilament peptides: A putative link between Al and Alzheimer disease." Proceedings of the National Academy of Sciences of the United States of America. 91 (1994): 4902-4906.

Jacqmin, Helene et al. "Components of Drinking Water and Risk of Cogitive Impairment in the Elderly." American Journal of Epidemiology. 139 (1994): 48-57.

Kuroda, Y. et al. "Application of Long-Term Cultured Neurons in Aging and Neurological Research: Aluminum Neurotoxicity, Synaptic Degeneration and Alzheimers Disease." Gerontology. 41 (1994): 2-6.

Lovell, M.A. et al. "Laser Microprobe Analysis of Brain Aluminum in Alzheimers Disease." Annals of Neurology. 33 (1993): 36-42.

Mattson, M.P. "Comparison of the effects of elevated intracellular aluminum and calcium levels on neuronal survival and tau immunoreactivity." Brain Research. 602 (1993): 21-31.

McLachlan, D.R. et al. "Desferrioxamine and Alzheimers Disease: Video Home Behavior Assesment of Clinical Course and Measures of Brain Aluminum." Therapeutic Drug Monitoring. 15 (1993): 602-607.

McLachlan, D.R. et al. "Risk for neuropathologically confirmed Alzheimers disease and residual aluminum in municipal drinking water employing weighted residential histories." Neurology. 46 (1996): 401-405.

This preliminary aluminum-soy assay needs to be repeated under more carefully controlled conditions to demonstrate or reject replicability. Since this one was paid for out of my pocket I leave the remaining work to interested parties.

-William Harris, M.D.
Honolulu, HI